1. Field of the Invention
The present invention relates to an air passage switching device and a vehicular air conditioner, which are constructed to open/close an air passage in an air duct by means of a rotary door.
2. Description of the Related Art
In an air conditioner for an automobile, for example, a compartment is fed through an air duct with a cool or warm wind which is prepared by a blower and a cooler (e.g., an evaporator) or a heater (e.g., a heater core). In this case, the air duct is equipped with air passages individually communicating with a plurality of outlets (e.g., FACE, FOOT, DEF and so on), and those air passages are opened/closed by a plurality of plate-shaped dampers on the basis of the operations of a blow mode switching lever in the compartment.
In this case, the blow mode switching lever is connected to one end of a control cable, which has its other end connected to a link mechanism to actuate the plurality of dampers. In the construction having these dampers to be actuated, the link mechanism is so considerably complicated as to increase the number of parts remarkably.
In Japanese Utility Model Application Laid-Open No. Sho 50-65151, on the other hand, there is disclosed a technique in which a cylindrical rotary damper is rotatably disposed in a distribution box so that the outlets may be switched by the single rotary damper. Moreover, the rotary damper is equipped at its outer circumference with a wind baffle plate which is made of a synthetic resin for preventing the wind leakage by coming into elastic contact with the inner face of the distribution box. As a result, the complicated link mechanism for actuating the plurality of dampers is eliminated to simplify the construction to an extent.
However, the aforementioned construction of Japanese Utility Model Application Laid-Open No. Sho 50-65151 may have the following disadvantages. Specifically, the wind baffle plate is a relatively rigid molding and may fail to come into complete contact with the inner face of the distribution box thereby to allow a wind leakage. After a long use or in a heated state, moreover, the wind baffle plate may creep to lose its elastic force thereby to cause the disadvantage of the wind leakage. Because of the structure for holding the wind baffle plate on the inner face of the distribution box, still moreover, the operating force required for turning the rotary damper is increased to invite another disadvantage that a sliding or chattering noise is caused.